System for automatically connecting and a disconnecting catenary vehicle to and from the overhead line during travel

ABSTRACT

A method and device for automatically connecting and disconnecting a current collector of a vehicle which is designed for operating with an overhead line. The invention specifies a device and a method for automatically connecting and disconnecting at least one current collector ( 3 ) of a vehicle which is designed for operation with at least one overhead line ( 1 ). The device comprises at least one actuator ( 9 ), which moves the current collector ( 3 ), and at least one image-capturing and image-evaluation unit ( 6  and  7 ), which controls the actuator ( 9 ) in such a way that the current collector ( 3 ) is connected or disconnected to or from the overhead line ( 1 ). The invention provides the advantage that current collectors of a vehicle can be reliably and securely connected and disconnected to and from an overhead line in an automatic fashion.

The invention pertains to a system consisting of a digital camera, actuators that act on the trolley pole current collectors, and an electronic control module, the system enabling catenary vehicles employing an associated method, in particular using stereoscopic pattern recognition and dynamic target tracking, to automatically connect and disconnect their current collectors to/from the overhead contact lines as needed during travel.

Electrically powered vehicles offer many advantages as compared to vehicles that obtain their primary source of energy from combustion engines. Since the efficiency of power storage or the clean generation of power using fuel cells is commonly considered to still be insufficient, power supply via overhead or other contact lines or via power rails provides an important alternative. In railbound vehicles such as trains or streetcars the prior art—known for over one hundred years—is sufficiently practical in practice and widespread. However, in non-railbound vehicles, in particular trolleybuses, the limitations of the prior art are so sizable that in many cities existing systems have been removed and replaced with diesel-powered buses. The key limitation of existing trolleybus methods lies in their insufficient flexibility, i.e. their lacking capability or capability that can be achieved only with substantial effort and expense, to also operate the trolleybus without power from the overhead line for a brief period of time.

Electric buses, also referred to as trolleybuses and catenary buses, are supplied with power via trolley poles primarily by way of dual-pole wire systems in the form of overhead lines. The lines are installed at a defined height, generally in the center above the designated lane. In so doing, the lines are not really parallel to one another on account of the manner in which they are affixed, i.e. the distance between the lines, typically ca. 60 cm, may vary within a range of ten centimeters or more. The height at which they are affixed is also subject to a sizable tolerance, ranging between 5 and 6 meters. An even larger tolerance is present with regard to their offset in relation to the middle of the lane, which may amount to as much as 4.5 m for 6.2-m-long poles. All of these factors pose an impediment to automatic connection to the overhead line, which is a prerequisite for a series of other application scenarios that would advance the desired electrical mobility essentially enabled with a trolleybus, particularly in inner-city areas.

The current collectors are usually featured as U-shaped collector shoes with swivel action around a vertical and a horizontal axis and located at the tip of each of the two pole current collectors. The collector shoes are pressed via the poles against the overhead lines by way of a vertically acting upward force so that electrical contact is continuous during the connection phase.

The existing systems are designed so that the current collectors remain connected over the entire distance traveled and are disconnected or at any rate are connected only when the vehicle is stopped. Since the construction of the line networks required for the continuous supply of power during the entire journey is not only expensive but their maintenance as well, in particular when they feature overhead switches for double or multiple lines along routes with bidirectional and multi-lane traffic, and since the line networks also involve other disadvantages such as esthetic restrictions, preventing them from being installed in historical town centers or in representational areas in particular, it is desirable to operate the vehicle off-wire over more or less short distances.

This not only means that an additional autonomous supply of energy is required in the vehicle, e.g. by way of batteries, capacitors, a combustion engine with a generator, fuel cells or a flywheel, but also a current collector system is required that is able to automatically disconnect from and, in particular, reconnect to the wires quickly and reliably. Various developments exist that address the question of the provision of power in the vehicle, e.g. dual-mode vehicles that feature a diesel generator on board, or the flywheel energy storage device described in DE 30 15 754 C enabling the generation of power for autonomous operation.

Suggested solutions have also been published on the problem of automatic reconnection, i.e. the controlled guidance of the current collector to the wires. In DE 24 60 843 it is suggested that an engagement aid, or “lug”, be vertically installed on either side of the collector shoes running parallel to the direction of travel that is designed to facilitate engagement and upon the contact being established is folded away in a downwards direction. The disadvantages of this system are that automatic connection using this device can only be made when the vehicle is stopped because the lug, when flipped out, projects into the area of the overhead wire suspension and guiding it to the overhead wire always requires manual interaction.

The proposal made in FR 2 506 234 boils down to an attempt to automate the process and in so doing reduce the measurement and control effort by affixing both of the current collector shoes to a common support. However, the implementation fails already—as indicated above—in that, by virtue of the principle, the overhead wires are never positioned in an exact predictable distance from one another.

Although the submitted solution of DE 100 54 766 solves the problem of the unreliable parallel positioning of the two overhead wires, it otherwise only reduces the control effort for guiding the collector shoes to the overhead line without providing a solution for the situation in which the overhead line is not precisely positioned in the middle of the lane or in a narrow corridor above the vehicle or for the situation in which the overhead line begins or ends while the vehicle is traveling.

The related invention of DE 100 12 039 C poses the additional disadvantage that it presupposes an entirely new and more complex technology and configuration of the overhead wire positioning and suspension.

What all of the aforementioned systems of propulsion have in common is that it is assumed that the position of the collector poles can be captured in relation to the vehicle and the overhead contact line and that this can be transformed into movement control without having provided concrete suggestions for this.

As a consequence, none of these systems has succeeded in being developed for use in practice: Either the entire length of the line is supplied by a continuous overhead wire, or the vehicles travel purely on electric power over specific sections, e.g. in tunnels, and are otherwise diesel-powered, and the current collector shoes are engaged in stationary devices, referred as “funnels”, either manually or, in the best case, semi-automatically. Conceptual designs that from the outset electrify continuous sections only a few meters long consistently omit intersections, underpasses, traffic turning left, steep downhill gradients etc. and consequently are dependent on a reliable and in particular quick automatic reconnection of the current collectors also while the vehicle is in motion, and are not to be found in the literature or in real life.

Consequently the purpose of the invention is to describe a current collector system together with the method utilized to this end that solves this problem, in particular the fully automatic disconnection and connection of the pole current collectors of a vehicle while traveling.

The purpose of the invention is accomplished by the device and the method of the independent claims.

The core of the invention is that by employing image capturing, image processing and image evaluation pole current collectors are able to automatically connect to an overhead line and disconnect from it.

The invention claims a device for automatically connecting and disconnecting at least one pole current collector of a vehicle which is designed for operation with at least one overhead line, using at least one actuator that moves the pole current collector, and using at least one image capturing and image evaluation unit to control the actuator so that the pole current collector connects to and disconnects from the overhead line. The invention offers the advantage that the current collectors of a vehicle can be reliably and securely connected to and disconnected from an overhead line in automatic fashion.

The invention also claims a method for automatically connecting and disconnecting at least one pole current collector of a vehicle which is designed for operation with at least one overhead line, with image capturing of the pole current collector and the overhead line, with image evaluation for determining the position of the pole current collector and the overhead line, and with control of an actuator forming a mechanical link to the pole current collector on the basis of image evaluation in such a manner that the pole current collector connects to and disconnects from the overhead line.

Vehicles are preferable that are equipped with two pole current collectors that connect to and disconnect from two overhead lines. Each of the two pole current collectors forms a mechanical link with at least one actuator each. The term “overhead line” is identical to “overhead (contact) wire”.

The purpose is also accomplished by a system consisting of stereoscopic moving image cameras, actuators for moving the pole current collectors and the contact shoes, and intelligent control electronics that determine the position of the overhead wires in relation to both the vehicle and the positions of the contact shoes and the current collector heads by way of optical pattern recognition on the basis of the data obtained by the video cameras, said system generating commands for the motor-powered and/or hydraulic or pneumatic positioning of the pole current collectors for the requisite connection and disconnection movements on the basis of its calculations and communication with other systems.

The aforementioned control electronics realize an upper command level that decides whether connection or disconnection is to be done and a lower level that monitors the movements of the pole current collector and contact shoe. Both levels utilize the information obtained by the cameras, i.e. moving images, and possibly further sensors, via which the relative positions of the contact shoes and overhead lines and also the visual surroundings, in particular any impediments between the contact shoe and the overhead line, are determined. The upper level is also able to utilize access to a global navigation satellite system for the purpose of determining the geoposition of the vehicle, the geoposition being synced using a card on which the areas with and without an overhead line or interruptions in the overhead line are recorded. The upper level is also able to utilize car-to-car communication based on digital radio with vehicles equipped in the same manner for the purpose of negotiating resource conflicts (involving the same overhead line) in which it is decided which of the involved vehicles is to remain connected and which vehicle (or vehicles) is (are) to (temporarily) disconnect.

Using statistical information (gained from past use) or other information, in particular an uphill and downhill gradient profile stored on the card, the upper level is also able to issue connect and disconnect commands to the lower level for the purpose of resource conservation, i.e. optimizing power usage and minimizing wear.

The invention is described in detail on the basis of an embodiment.

FIG. 1 shows the relevant mechanical components associated with a vehicle using the example of a trolleybus in a side view.

FIG. 2 shows the same situation in a rear view.

FIG. 3 illustrates the method for determining the position of the overhead line.

The figures show the use of the invention in the context of a trolleybus in which the active movement of the pole current collectors (3) is effected via arrestor cable motors (9) and the arrestor cables (4) are tensioned by way of the force generated by the compression springs (5). The stereoscopic video cameras (6) are affixed to the roof of the bus and transmit their image data to the control electronics, also mounted on the roof (7), the control electronics transmitting control commands for the actuators, i.e. in this example the arrestor cable motors.

In so doing, the control electronics utilize the method of the invention described below in order to, as needed, position the pole current collectors along with the contact shoes (2) as close as possible underneath the overhead line (1), where present, so that electrical contact is made. Conversely, the relevant control commands for the actuators are generated for disconnecting or possibly anchoring the pole current collectors in the locking device (8) in areas in which it is disadvantageous or deleterious to travel while connected according to the operating conditions computed by the control electronics or where there is no longer any overhead line within the reach of the pole current collectors.

In so doing, the positions of the two overhead wires are identified as two essentially straight lines in a two-dimensional picture of the video images of the aforementioned cameras employing pattern recognition methods, the wires corresponding to a “left” and a “right” wire. The two wires each establish a plane (10) in relation to the vehicle by way of inverse projection in three-dimensional space. By performing computations so that the left and right planes of the two images of the two cameras intersect in three-dimensional space, i.e. the left planes intersecting and the right planes intersecting, a left line and a right line (11) are obtained in three-dimensional space, always relative to the position of the vehicle. The two current collectors must be positioned in place from below along these two lines for connection. To this end, the position of the contact shoes on the pole current collectors is also determined stereoscopically in space in an analogous manner, corresponding curves computationally established in space via which the contact shoes are guided to the overhead wires, and the pole mechanism controlled in a manner such that the contact shoes approach the overhead wires proceeding along the computed curves. Since all of this takes place while the vehicle is traveling, i.e. the position of the overhead wires in relation to the vehicle changing in particular, the current and target positions and the control commands derived from them must be constantly recalculated anew.

The method for disconnection is analogous, only that, depending on the embodiment, the position of the overhead wires no longer plays a role.

In addition, the control module continuously monitors the overhead wires during the connected and disconnected state so as to answer the following questions:

-   -   Do the overhead wires proceed outside of the corridor in         relation to the vehicle, the corridor within reach of the         contact shoes, i.e. does the vehicle leave the lane area?     -   Or do the overhead wires return to this corridor?     -   Or do the overhead wires come to an end?     -   Or do they resume?     -   Is there an obstruction underneath the overhead wires, e.g. the         contact shoes of another vehicle in particular, and can the         orientation and speed of movement of the obstruction be         determined in relation to the vehicle?     -   Is the vehicle currently in a connected or disconnected state?

The advantages achieved with the invention are that a significant simplification of the line routing can be achieved, however the time during which the vehicle draws power from the overhead line is maximized.

In addition, proven standard components can be used for the mechanical part.

Another advantage is that now for the first time connection and disconnection can be provided for within the space of a few seconds, this also enabling frequent changes of journeys with and without contact to the overhead line and a flexible reaction to unforeseen operating conditions, e.g. driving around an obstacle that has just arisen, e.g. after an accident.

Thanks to the fully automatic operation enabled, all this can take place without posing a burden to the driver or resorting to manual intervention.

The aforementioned optical pattern recognition utilizes in particular the method of tracking a sluggishly moving target in which the future target can be inferred from the movement so far, so that in the event of difficult visibility conditions, e.g. pouring rain or snow, reliable recognition of the overhead wires can be ensured. In order to ensure reliable function in darkness, small lamps suffice, e.g. infrared LEDs as are frequently integrated in surveillance cameras.

The aforementioned target tracking method utilizes the following principle:

The dynamic positions of the overhead wires more or less expected on the basis of previous recognitions by extrapolating their past movement within a two-dimensional video image are evidenced in the computation of the subsequent situation with a (significantly) higher probability in that the pattern being sought is encountered (again).

In addition, in a connected state the position of the pole current collector or contact shoe computed and possibly determined by sensors can be used for determining the position of the overhead wires.

For verification purposes the bus driver can also be provided with the image captured by the cameras in the dashboard, the images showing the overhead contact lines and pole current collectors. If no overhead contact line is recognized, no connection takes place or disconnection takes place automatically.

Entry into areas in which vehicle operation is to be done in a connected state, i.e. those areas in which overhead wires are installed in principle, is recognized by a global navigation satellite system, e.g. GPS (i.e. the American global positioning system), or its future European counterpart Galileo, and an integrated card. Exiting these areas, e.g. at end of the network, underpasses and tunnels with insufficient clearance for overhead wires, or construction sites forcing the vehicle to depart from its normal lane, is detected in an analogous manner and results in scheduled disconnection. The same applies to turn-offs, which consequently no longer require (overhead) switches as such and which are costly and subject to wear and tear: the line branching off resumes at a somewhat extended distance from the turn-off, vehicles turning off disconnect briefly in this area and then reconnect to the new line. The same applies to intersections with other overhead lines and those of trams and trains at which the intersecting pair of overhead contact lines or one of the two intersecting pairs of overhead contact lines is interrupted briefly. Also areas in which overhead wires would be intrusive for esthetic or other reasons could be omitted using this approach.

In a disconnected state the vehicle would draw power from a storage device (flywheel, battery or capacitors) and/or from a supplementary combustion engine (APU (auxiliary power unit), hybrid operation or fuel cell).

The storage device, where present, is recharged using recuperation energy and/or from the overhead wire, or possibly from the APU employing intelligent heuristics in the control module pertaining the expected subsequent use of the storage device, the route yet to be traveled by the vehicle and its energy requirement profile being known.

Provision can be made to update the integrated card as needed via digital radio (GSM/UMTS or trunked radio) also while the vehicle is traveling.

The optical control module enables a continuous comparison to be made between the card (target) and the actual situation as-is. Where a discrepancy occurs, e.g. “overhead wire unexpectedly missing”, feedback is given to the driver and transmitted via digital radio to an operations center.

The optically captured data is continuously recorded in a ring buffer (silicon disk) (video as log) and can be used for subsequent problem analysis.

Scheduled disconnection in (extended) sections in which little operating power is required or little recuperation energy is recovered (e.g. extended section with a slight gradient) can be used to reduce wear to the current collector and the overhead contact wires.

Sections of this kind may be featured entirely without any overhead wire.

In areas with two-way traffic, a common overhead line can be used for both directions of travel, local conditions permitting. When two buses meet, the two vehicle control modules automatically negotiate via digital radio which of the two buses will disconnect briefly until they have passed one another (car-to-car communication). Priority rules can be stored on the aforementioned card so that the bus disconnects that can be expected to draw less power from the network. The circumstance that two buses will meet can be detected via digital radio (position reporting of the individual buses) or via transponder. Any failure of automatic communication (e.g. outage of digital radio) can be detected via the optical surveillance and results in the emergency disconnection of both buses.

Disconnection is also initiated while passing—whether detected automatically or explicitly announced by the driver—and also generally where there are parallel lanes proceeding in the same direction with a jointly used overhead line.

Automatic disconnection also occurs when the target area of the pole current collector leaves the area of the overhead wires, e.g. when going around a construction site or an accident. Automatic reconnection takes place as soon as the bus has traveled a sufficient distance back into the area of the overhead wires.

The result is a system that economically provides for high operational reliability. 

1. Device for automatically connecting and disconnecting at least one pole current collector (3) of a vehicle which is designed for operation with at least one overhead line (1), using at least one actuator (9) that moves the pole current collector (3), characterized by at least one image capturing and image evaluation unit (6 and 7) which controls the actuator (9) in such a way that the pole current collector (3) connects to or disconnects from the overhead line (1).
 2. Device according to claim 1, characterized by stereoscopic cameras of the image capturing and image evaluation unit (6) which capture a stereoscopic image of the pole current collector (3) and the overhead line (1).
 3. Device according to claim 2, wherein characterized in that the image capturing and image evaluation unit (6 and 7) controls the actuator (9) by way of pattern recognition.
 4. Device according to claim 3, characterized by an electronic circuit with communication and storage elements which positions a contact shoe (2) of the pole current collector (3) on the basis of a signal of the stereoscopic cameras (6) and other input variables by way of control commands to the actuator (9) in such a way that electric contact of the contact shoe (2) can be made with the overhead line (1).
 5. Device according to claim 1, characterized by two pole current collectors (3) each with one contact shoe (2), two overhead lines (1) and at least two actuators (9) that separately or jointly move the two pole current collectors (3).
 6. Method for automatically connecting and disconnecting at least one pole current collector (3) of a vehicle which is designed for operation with at least one overhead line (1), characterized by image capturing of the pole current collector (3) and the overhead line (1), image evaluation for determining the position of the pole current collector (3) and the overhead line (1) and control of an actuator (9) forming a mechanical link to the pole current collector (3) on the basis of image evaluation in such a manner that the pole current collector (3) connects to or disconnects from the overhead line (1).
 7. Method according to claim 6, wherein characterized in that image capturing and image evaluation take place stereoscopically.
 8. Method according to claim 6, wherein characterized in that image evaluation is done by way of pattern recognition.
 9. Method according to claim 8, wherein characterized in that the control system determines commands for the actuator (9) on the basis of a computed position of the overhead line (1) and a contact shoe (2) of the pole current collector (3), whereby the overhead line (1) is identified as a largely straight line via the two-dimensional images captured by the cameras (6), on the basis of which two almost level planes (10) each are computed in three-dimensional space relative to the vehicle whose projection results in the largely straight lines in the two-dimensional image and in which the overhead line (1) consequently must run, according to which the two planes are intersected and thus a largely straight line relative to the vehicle is obtained in space as the intersection set (11), and in an analogous manner the position of an associated contact shoe (2) of the pole current collector (3) is also determined stereoscopically in space as the approximate intersection of the lines in space that are determined by projecting an appropriately selected point of the contact shoe (2) in both of the two-dimensional images.
 10. Method according to claim 9, wherein characterized in that the command for connection and disconnection, i.e. for applying the pole current collector (3) to the overhead line (1) and for retracting and/or anchoring it in a pole locking device (8), is issued by a higher level in the control system, said control system being based on a digital card on which areas in which the vehicle is to be operated in a connected state are marked on a route map, and when the vehicle leaves these areas the command is issued for automatically disconnecting and, vice versa, when the vehicle reaches an area with the overhead line (1) automatic connection can be ordered, whereby in each case a position of the vehicle on the digital card is determined via a global navigation satellite system.
 11. Method according to claim 9, wherein characterized in that instead of conventional switches for branching overhead lines (1) the overhead line (1) resumes after the turn-off and that the control system ensures that a vehicle turning off briefly disconnects in the switch area and then reconnects to the resuming overhead line (1), which analogously applies to situations in which the vehicle passes through an intersection and the overhead line (1) assigned to it is interrupted.
 12. Method according to claim 9, wherein characterized in that brief disconnection is also initiated by the control system in such a manner that, when the vehicle encounters another vehicle equipped in the same manner or passes one using the same overhead line (1), the two vehicles communicate with one another via a digital radio link (7) and cooperatively determine which of the vehicle disconnects.
 13. Method according to claim 9, wherein characterized in that the control system also generally initiates disconnection when the optical pattern recognition signals an unforeseen interruption or an obstacle, in particular the pole current collector (3) of another vehicle where digital radio communication is impaired, when an obstacle is detected by mechanical sensors, e.g. an optically undetected current collector of another vehicle, or when a vehicle driver issues a relevant command.
 14. Method according to claim 9, wherein characterized in that the control system—on the basis of the previous position of the overhead line (1) as an almost straight line in space and a motion vector of the vehicle that results from its previous and current differential speed and orientation in the street space and hence relative to the overhead line (1)—establishes a corresponding new possible position for the overhead line (1) as a line in the two-dimensional images of the cameras (6) with a high probability and uses this result in optical pattern recognition.
 15. Method according to claim 9, wherein characterized in that the control system computes by way of the integrated digital card on which the route to be traveled by the vehicle is entered—in combination with position determination and statistical methods in the form of continuously acquired empirical values for the purpose of energy optimization—in which areas secondary energy from an energy storage device will be needed, whereby an elevation profile of the terrain can also be referenced for determining the sections with an uphill or downhill gradient, in order to disconnect also for the purpose of minimizing wear in the latter case.
 16. Method according to claim 9, wherein characterized in that the control system determines an energy flow in the vehicle employing an expected consumption profile such that also when the vehicle is in a connected state a portion of the operating energy is drawn from the energy storage device or recuperative energy is fed into a line network from traction motors or even from the energy storage device or such that, conversely, simultaneous charging of the energy storage device takes place via the overhead line (1). 